The present invention generally relates to toilets and, more particularly, to vacuum toilet systems.
Vacuum toilet systems are generally known in the art for use in both vehicle and stationary applications. A vacuum toilet system typically comprises a bowl for receiving waste having an outlet connected to a vacuum sewer line. A discharge valve is disposed between the bowl outlet and vacuum sewer line to selectively establish fluid communication therebetween. The vacuum sewer line is connected to a collection tank that is placed under partial vacuum pressure by a vacuum source, such as a vacuum blower. When the discharge valve is opened, material in the bowl is transported to the sewer pipe as a result of the pressure difference between the interior of the bowl and the interior of the sewer line. Conventional vacuum toilet systems also include a source of rinse fluid and a rinse fluid valve for controlling introduction of rinse fluid into the bowl.
The components of a conventional vacuum toilet are typically provided separately and are overly difficult to assemble. The discharge valve is typically mounted in a first position, while the rinse valve is mounted in a second, separate position. A flush control unit (FCU) is mounted remote from both valves and provides control signals to the discharge and rinse valve actuators. Accordingly, various mounting brackets, tubing, and wires are needed to interconnect the various components, making assembly overly complicated and time-consuming.
In addition, the separate components used in conventional vacuum toilets make repair and maintenance overly time consuming and labor intensive. Maintenance concerns are particularly significant in aircraft applications, in which a number of sub-systems are installed on board. According to general practice in the airline industry, each sub-system includes one or more components which must be replaced in the event of failure, such replacement components being commonly referred to as line replaceable units (LRUs). Presently, the entire vacuum toilet is defined as the LRU for the vacuum toilet system. As a result, an airline must stock one or more replacement toilets in the event of a toilet failure, so that the replacement toilet may be swapped in for the faulty toilet. A xe2x80x9cbench testxe2x80x9d is then performed on the faulty toilet to determine which components have failed in the toilet. The faulty components are then repaired or replaced (which may include significant disassembly and reassembly of the toilet) so that the toilet may be reused on another aircraft.
Each of the steps performed during a toilet repair is overly difficult and time consuming. To remove an entire toilet assembly from an aircraft requires disassembly of at least four self-locking mounting fasteners, an electrical connection, a grounding strap, a potable water line connection, and a waste discharge pipe connection. Each connection may be difficult to access, and may require a particular tool in order to loosen and disconnect. The same connections must then be reconnected for the replacement toilet.
Even if it were possible to remove and replace a single toilet component, it would be overly difficult and time consuming to do so. Removal of a component would require disconnection of several wires and pipes, and the components are often located in areas which are difficult to access. Furthermore, it would be difficult to diagnose whether one component or several components had failed. There exists a multitude of combinations of simultaneous component failures, which may lead to trouble-shooting errors and the replacement or repair of non-faulty components.
In view of the foregoing, it is apparent that the replacement and repair of conventional toilets is overly time consuming, and requires an airline to maintain a large stock of replacement toilets in the event of equipment failure.
Other repairs, which may not require substantial amounts of trouble shooting to identify the failed components, still require significant amounts of disassembly and reassembly. The toilet bowl, for example, is typically formed of stainless steel covered with a non-stick coating that is subject to failure. In conventional toilets, the bowl is a structural, load bearing component that is attached to a base support. In some toilets, the base support is permanently attached to the bowl and therefore the entire toilet must be removed to replace the coating. In other toilets, the bowl is removable from the support base, and therefore fasteners must be removed and the bowl must be disconnected from the rinse fluid and discharge lines. In addition, the rinse ring or nozzle used to direct rinse fluid into the bowl must be removed. Furthermore, if the non-stick coating fails, the bowl must be removed from all of the other toilet components for a re-coating process, steps of which are performed at high temperature to remove the old coating and apply a new coating to the toilet bowl surface. Accordingly, the replacement of a conventional bowl is overly complicated and time consuming.
From the foregoing, it will be appreciated that a number of toilets must be kept in stock for replacement in the event of a faulty toilet. The number of stock toilets is further increased due to the left-handed and right-handed discharge configurations of conventional vacuum toilets. Typically, the component layout of a conventional vacuum toilet must be modified according to the type of discharge configuration desired. In addition, different components maybe required, such as a toilet bowl with a left-handed or right-handed discharge. As a result, an airline must have both left- and right-handed discharge replacement toilets on hand, thereby increasing the number of stock parts required.
From the above, it will be appreciated that a need exists for a vacuum toilet that is easier to maintain and which reduces the number of stock parts required.
In accordance with certain aspects of the present invention, a modular vacuum toilet is provided for use in a vacuum toilet system having a sewer line placeable under partial vacuum pressure and a source of rinse fluid. The modular vacuum toilet comprises a support structure, and a removable bowl supported by the support structure, the bowl defining an outlet and having a rinse fluid dispenser associated therewith. A valve set module is provided having a discharge valve with an inlet in fluid communication with the bowl outlet, an outlet in fluid communication with the sewer line, and a movable discharge valve member disposed between the discharge valve inlet and outlet; a rinse fluid valve having an inlet in fluid communication with the source of rinse fluid, an outlet in fluid communication with the rinse fluid dispenser, and a movable rinse fluid valve member disposed between the rinse fluid valve inlet and outlet; and a flush control unit having a circuit board operably connected to the discharge. valve and rinse fluid valve for controlling actuation of the discharge valve member and rinse fluid valve member.
In accordance with additional aspects of the present invention, a method of servicing a vacuum toilet is provided, in which the vacuum toilet is attached to a vacuum toilet system having a sewer line placeable under partial vacuum pressure and a source of rinse fluid, and in which the vacuum toilet includes a waste receptacle defining an outlet and having a rinse fluid dispenser associated therewith. The method comprises providing a first valve set module having a discharge valve with an inlet adapted to engage the receptacle outlet and an outlet adapted for releasable connection to the sewer line, a rinse fluid valve with an inlet adapted for releasable connection to the source of rinse fluid and an outlet adapted for releasable connection to the rinse fluid dispenser, and a flush control unit adapted to control operation of the discharge valve and rinse fluid valve. The discharge valve is detached from the bowl outlet, discharge valve outlet from the sewer line, the rinse fluid valve inlet from the rinse fluid source, and the rinse fluid valve outlet from the rinse fluid line, and the valve set module is removed from the vacuum toilet. A second valve set module is inserted into the vacuum toilet, the second valve set module including a discharge valve with an inlet adapted to engage the receptacle outlet and an outlet adapted for releasable connection to the sewer line, a rinse fluid valve with an inlet adapted for releasable connection to the source of rinse fluid and an outlet adapted for releasable connection to the rinse fluid dispenser, and a flush control unit adapted to control operation of the discharge valve and rinse fluid valve. The second valve set discharge valve inlet is then attached to the bowl outlet, the discharge valve outlet to the sewer line, the rinse fluid valve inlet to the rinse fluid source, and the rinse fluid valve outlet to the rinse fluid line.
In accordance with further aspects of the present invention, a method of servicing a vacuum toilet is provided wherein the toilet has a receptacle for receiving waste defining an outlet and includes a rinse fluid dispenser associated therewith. A discharge valve has an inlet in fluid communication with the receptacle outlet, an outlet in fluid communication with a sewer line placeable under partial vacuum pressure, and a moveable discharge valve member disposed between the discharge valve inlet and the discharge valve outlet. A rinse fluid valve has an inlet in fluid communication with a source of rinse fluid, an outlet in fluid communication with the rinse fluid dispenser, and a moveable rinse fluid valve member disposed between the rinse fluid valve inlet and the rinse fluid valve outlet. A flush control unit is adapted to control actuation of the discharge valve member and rinse fluid valve member, in which at least one of the discharge valve, rinse fluid valve, flush control unit, and waste receptacle is a line replaceable unit. The method comprises removing the faulty line replaceable unit from the toilet, and installing a new line replaceable unit into the toilet.
In accordance with still further aspects of the present invention, a valve set is provided for use in a vacuum toilet system having a sewer pipe placeable under partial vacuum pressure. The valve set comprises a discharge valve having an outlet, and an outlet pipe attached to the discharge valve outlet and defining a branch. A discharge pipe has a first end adapted to releasably engage the sewer pipe and a second end releasably attachable to the branch in at least a first position corresponding to a left-handed discharge configuration and a second position corresponding to a right-handed discharge configuration.
Other features and advantages are inherent in the apparatus claimed and disclosed or will become apparent to those skilled in the art from the following detailed description and its accompanying drawings.